Haojv, sorry to learn of your baking mishap. I had a few moments & I visted that site & located the recipe. I am asking my friend the reason of your post… is it you are asking for a member to provide you with a fix for this recipe???. If you are, are you willing to try once again???
I can provide you with a fix, of course, there are no guarantees.

Thanks for telling us where to find the recipe! It sounds delicious, but very rich. It’s like a cake recipe with the flour considerably reduced, and dates & nuts added.

Several reviews on allrecipes.com suggest that you should reduce the butter, and maybe the sugar as well, so that sounds like something to try.

Perhaps the butter is coming out of emulsion? Try being very careful to have the butter and eggs at cool room temperature—not too hot and not too cool. And cream the butter and sugar thoroughly before adding the other ingredients. Beat in the other ingredients gradually, not adding too much all at once.

You could also try the “high-ratio” method of mixing—the one Rose uses throughout the “Cake Bible.”

You know how Rose’s cake recipes can be kind of “greasy” if you use all-purpose flour when cake flour is called for??? Well, why not do the opposite for this recipe - use cake flour in place of the all-purpose. Cake flour is bleached - a process which enables the flour to absorb the fat better.